Direct synthesis of 2,5-diformylfuran from carbohydrates via carbonizing polyoxometalate based mesoporous poly(ionic liquid)

•Polyoxometallate based mesoporous poly(ionic liquid) was partially carbonized.•Partial carbonization strengthened the acid and oxidation property.•Target catalyst was highly active in the synthesis of DFF from carbohydrates.•High yield and TON was achieved in a one-pot and one-step reaction.•Various carbohydrates were effectively converted into DFF.